Interesting. Do you have any links to those studies you mention?
Rather than pointing out one or two sources (one can always find a couple of references that support any opinion or statement

), talk to conscious athletes and trainers; check out your local bookstore and skim through chapters in books about various sports, exercise, workout routines and sports medicine; Google around.
As I get older (30+ now), I find I need to stretch more to just maintain the range of motion I had yesterday. So this isn't technically about increasing flexibility, just not losing it.
I hear you

Ever notice when a dog or cat gets up? They always immediately do some stretching before walking. I think they are instinctively on to something.
There is a big difference between an occasional stretch and systematic stretching. Over time, tension builds up in muscles, which can often be relieved by a quick stretch, e.g. during yawning in the morning, every now and then during a work day, etc. This is the mild form of using stretching for therapeutic purposes. Yet, it happens often enough that people pull muscles during those casual stretches. I have done so, and everybody around me I cared to ask about has done so too.
Also, all the athletes (olympics) stretch and make sure their muscles are loose before their events. I doubt they ALL have injured muscles.
They probably do all have injuries. Most top-athletes are not deemed fit for military service, but that is besides the point. When you see these athletes stretch, their muscles are already thoroughly warmed up. There is nothing wrong with that as I have stated in my first post.
I am not warning against stretching in general. In fact, I whole-heartedly agree with the advice that says "Proper stretching is good". The question is: what is "proper"? I am only warning against stretching in order to increase the range of motions and stretching without having first properly warmed up the involved muscles.